Allow larger write queues for large nodes (#130061)

With the rise of larger CPU count nodes our current write queue size
might be too conservative. Indexing pressure will still provide protect
against out of memories.

Author: Tim-Brooks

docs/reference/elasticsearch/configuration-reference/thread-pool-settings.md

@@ -33,7 +33,7 @@ $$$search-throttled$$$`search_throttled`
 :   For analyze requests. Thread pool type is `fixed` with a size of `1`, queue size of `16`.
 
 `write`
-:   For write operations and ingest processors. Thread pool type is `fixed` with a size of [`# of allocated processors`](#node.processors), queue_size of `10000`. The maximum size for this pool is `1 + `[`# of allocated processors`](#node.processors).
+:   For write operations and ingest processors. Thread pool type is `fixed` with a size of [`# of allocated processors`](#node.processors), queue_size of `max(10000, (`[`# of allocated processors`](#node.processors)`* 750))`. The maximum size for this pool is `1 + `[`# of allocated processors`](#node.processors).
 
 `write_coordination`
 :   For bulk request coordination operations. Thread pool type is `fixed` with a size of [`# of allocated processors`](#node.processors), queue_size of `10000`. The maximum size for this pool is `1 + `[`# of allocated processors`](#node.processors).

server/src/main/java/org/elasticsearch/threadpool/DefaultBuiltInExecutorBuilders.java

@@ -54,7 +54,8 @@ public Map<String, ExecutorBuilder> getBuilders(Settings settings, int allocated
                 settings,
                 ThreadPool.Names.WRITE,
                 allocatedProcessors,
-                10000,
+                // 10,000 for all nodes with 8 cores or fewer. Scale up once we have more than 8 cores.
+                Math.max(allocatedProcessors * 750, 10000),
                 new EsExecutors.TaskTrackingConfig(true, indexAutoscalingEWMA)
             )
         );